There is a wide variety of online collaborative sessions such as social web group discussion threads (asynchronous or synchronous), chat rooms, online meetings, web conferences, and presentations (e.g. WebEx™, GoToMeeting™, etc.), online training and educational classes (e.g. WizIQ™, DimDim™, Blackboard™, etc.), and even online co-editing of documents (DropBox™, GoogleDocs™, etc.).
Sharing hyperlinks (“links”) or universal resource locators (URLs) to on-line meeting rooms is a common scenario in an online collaboration environment. A potential user or participant may not be aware of the login information an ongoing virtual meeting, for example, so he or she may contact someone that is currently a participant in the online meeting room to ask for the meeting URL and password. The contacted participant might respond by sending to the potential user the URL to the online meeting room in the form of a forwarded electronic message (email, SMS, IM, etc.), or verbally via a phone call or online voice connection. For most scenarios, this makes sense, and doesn't cause any issue.
However, some critically sensitive online collaborative sessions may contain information that could be sensitive, confidential, or even illegal to share outside of a small group, such as information about a resource action, a company acquisition, or future earnings that have not been made public. Such sharing of information introduces legal, commercial and even national security ramifications, where an uninvited user who has been informed with enough information about the on-line meeting room (or document or thread, etc.), can join the on-line room, and thus not comply with any number of policies, legal or otherwise.